{
  "node": {
    "id": "term:structural-degradation",
    "type": "Term",
    "label": "Structural degradation",
    "properties": {
      "id": "structural-degradation",
      "name": "Structural degradation",
      "aka": [
        "phase transformation",
        "cation mixing"
      ],
      "section": "topic-aging",
      "definition": "Changes in the crystal structure of a positive material as it cycles: layered oxides can rearrange into spinel or rock-salt phases at the surface, with nickel ions migrating into lithium sites. The new phases block lithium transport and raise resistance.",
      "related": [
        "high-nickel",
        "phase-transition",
        "impedance-rise",
        "loss-of-active-material"
      ],
      "url": "https://lemonergy.com/learn/glossary/structural-degradation/",
      "mentions": [
        "lmo"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:1569",
      "source": "term:structural-degradation",
      "target": "topic:topic-aging",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:1570",
      "source": "term:structural-degradation",
      "target": "term:high-nickel",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1571",
      "source": "term:structural-degradation",
      "target": "term:phase-transition",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1572",
      "source": "term:structural-degradation",
      "target": "term:impedance-rise",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1573",
      "source": "term:structural-degradation",
      "target": "term:loss-of-active-material",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/structural-degradation/lmo",
      "source": "term:structural-degradation",
      "target": "term:lmo",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:1575",
      "source": "term:structural-degradation",
      "target": "reference:edge-degradation",
      "type": "cites",
      "properties": {
        "sourceFile": "wiki-references.json",
        "scope": "direct technical reference"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-aging",
      "type": "Topic",
      "label": "Aging and degradation",
      "properties": {
        "id": "topic-aging",
        "name": "Aging and degradation",
        "lede": "Why a cell loses capacity and gains resistance, and the mechanisms behind it.",
        "context": "Separate mechanisms, observations and fitted models.",
        "example": "Capacity loss and resistance rise can have different causes; a film-growth curve cannot identify both.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-aging/",
        "lesson_label": "Open aging"
      }
    },
    {
      "id": "term:high-nickel",
      "type": "Term",
      "label": "High-nickel cathode",
      "properties": {
        "id": "high-nickel",
        "name": "High-nickel cathode",
        "aka": [
          "Ni-rich"
        ],
        "section": "topic-chemistries",
        "definition": "A layered oxide with 80 % or more nickel, such as NMC811 or NCA. Nickel raises capacity and lowers cobalt content, but the material is less thermally stable, more sensitive to moisture and ages faster at high voltage.",
        "related": [
          "nmc",
          "nca",
          "cathode-active-material",
          "thermal-runaway",
          "cei",
          "mid-nickel"
        ],
        "url": "https://lemonergy.com/learn/glossary/high-nickel/",
        "mentions": [
          "cobalt",
          "layered-oxide"
        ]
      }
    },
    {
      "id": "term:phase-transition",
      "type": "Term",
      "label": "Phase transition",
      "properties": {
        "id": "phase-transition",
        "name": "Phase transition",
        "aka": [
          "staging"
        ],
        "section": "topic-electrochemistry",
        "definition": "A change of crystal structure as lithium content varies, which fixes the potential while two phases coexist. Graphite fills in stages, LFP switches between two phases across almost its whole range, and these transitions make the peaks that aging diagnostics read.",
        "related": [
          "voltage-plateau",
          "differential-voltage-analysis",
          "lfp",
          "graphite",
          "structural-degradation"
        ],
        "url": "https://lemonergy.com/learn/glossary/phase-transition/",
        "mentions": []
      }
    },
    {
      "id": "term:impedance-rise",
      "type": "Term",
      "label": "Impedance rise",
      "properties": {
        "id": "impedance-rise",
        "name": "Impedance rise",
        "aka": [
          "resistance growth",
          "power fade"
        ],
        "section": "topic-aging",
        "definition": "An increase in a cell’s internal resistance as it ages. It costs voltage under load and therefore power, even while the stored charge is still there.",
        "related": [
          "internal-resistance",
          "sei",
          "cei",
          "state-of-power",
          "state-of-health"
        ],
        "lesson": "fundamentals/battery-aging/#crystals",
        "url": "https://lemonergy.com/learn/glossary/impedance-rise/",
        "mentions": [
          "closed-circuit-voltage"
        ]
      }
    },
    {
      "id": "term:loss-of-active-material",
      "type": "Term",
      "label": "Loss of active material",
      "properties": {
        "id": "loss-of-active-material",
        "name": "Loss of active material",
        "abbr": "LAM",
        "section": "topic-aging",
        "definition": "The degradation mode in which electrode material becomes unable to store lithium: particles crack and lose electronic contact, structures collapse, or transition metals dissolve. It is tracked separately for each electrode.",
        "related": [
          "particle-cracking",
          "transition-metal-dissolution",
          "loss-of-lithium-inventory",
          "capacity-fade"
        ],
        "url": "https://lemonergy.com/learn/glossary/loss-of-active-material/",
        "mentions": [
          "electrode",
          "aging-mechanism"
        ]
      }
    },
    {
      "id": "term:lmo",
      "type": "Term",
      "label": "LMO",
      "properties": {
        "id": "lmo",
        "name": "LMO",
        "aka": [
          "lithium manganese oxide",
          "spinel"
        ],
        "section": "topic-chemistries",
        "definition": "A manganese spinel positive material, LiMn₂O₄, that is cheap, safe and good at high power but suffers manganese dissolution and short life at elevated temperature. It is often blended with NMC rather than used alone.",
        "related": [
          "transition-metal-dissolution",
          "nmc",
          "cathode-active-material",
          "lnmo"
        ],
        "url": "https://lemonergy.com/learn/glossary/lmo/",
        "mentions": [
          "manganese"
        ]
      }
    },
    {
      "id": "reference:edge-degradation",
      "type": "Reference",
      "label": "Lithium ion battery degradation: what you need to know",
      "properties": {
        "title": "Lithium ion battery degradation: what you need to know",
        "publisher": "Physical Chemistry Chemical Physics",
        "url": "https://doi.org/10.1039/D1CP00359C",
        "type": "Review article",
        "scope": "Degradation mechanisms, modes, operational effects and their interactions.",
        "year": 2021,
        "accessed": "2026-10-27"
      }
    }
  ]
}